When a company's business is insuring the financial futures of individuals and companies around the world, it knows the benefits of planning ahead. That's why when St. Paul, Minn.-based Minnesota Life needed to expand, it enlisted a building team with the same knack for preparation and developed a strategy that not only supports the company's growth plans, but also the development objectives of the city of St. Paul. The result of this detailed design is the new $103 million 401 Robert Building — a 13-story, L-shaped facility that offers 635,000 square feet of office, underground parking and retail space to employees and city residents.
A contract for collaboration
Having owned and operated its own building in St. Paul since the 1950s, Minnesota Life knew that in order to deliver on its and the city's goals, it needed a building team dedicated to communication — not only among team members, but also with its own experienced staff. From the outset, the negotiated-bid project was managed with weekly design meetings that included owner representatives and key subcontractors, St. Paul-based contractor McGough Construction Co. Inc. and Minneapolis-based firms that included architect Architectural Alliance; structural engineer Meyer, Borgman & Johnson; mechanical/electrical engineer Michaud Cooley Erickson; and leasing and marketing manager Welsh Companies.
According to Julio Fesser, manager of corporate space planning with Minnesota Life, this open communication and evaluation of design options provided a great deal of both time and cost savings. "Having everyone at the table enabled the team to make informed decisions about materials and design details before we committed to them," says Fesser, who credits the team's project intranet along with the meetings as the key communication tools. "Simply put, the success of the project is due to the collaborative prowess of the building team."
One of the first challenges was determining whether to construct a new building. When Minnesota Life commissioned its 21-story headquarters — the 400 Robert Building — 20 years ago, it included room for an additional office tower. While a new tower might have relieved current growing pains — which necessitated leasing some 120,000 square feet of supplemental office space in the downtown area — it would not have accommodated the company's space needs with an anticipated 3 to 5 percent annual growth rate. "Basically the company had two options — build the tower to tackle the immediate need, or overbuild by adding a new structure and lease the extra space," says Thomas McGough Jr., chief operating officer, McGough Construction. After reviewing the vacancy rates in the booming Twin Cities area, overbuilding seemed preferable.
Sited across the street from the 400 Robert building, 401 Robert works as an extension of the company's older building via a connecting underground service tunnel and second-floor skywalk. And with its state-of-the-art infrastructure, the building bridges the company into the future. The new building offers class-A amenities rare in downtown St. Paul, including 52,000-sq.-ft. floor plates, an expandable communications infrastructure and automated elevator and mail systems. "400 Robert's 17,000-sq.-ft. floorplates often limited necessary department adjacencies and hindered group interaction," says Thomas DeAngelo, principal with Architectural Alliance. 401 Robert's cast-in-place concrete system and 43-ft.-long post-tensioned beams enable it to accommodate desired department configurations.
Considered to be the most technologically advanced building in St. Paul, 401 Robert is outfitted with a high-speed fiber-optic backbone that can be accessed from one of many distribution closets or from the raised access flooring installed throughout the building. "The primary goal was not to have new technologies hampered because of the building's design," says Monty Talbert, vice president and principal with Michaud Cooley Erickson.
"A key concern for the new building was how to address elevator congestion, which was a major problem at 400 Robert," notes Fesser. Solving the "rush-hour" traffic problem is the elevator control system that groups occupants by destination for fast service. Passengers enter their desired floor into a keypad and are assigned their elevator car based on similar destinations. The expected efficiencies of the system enabled the team to eliminate one car from the original design, leaving 11 to accommodate the building's 2,000-plus occupants.
Providing similar efficiencies, a new automated mail system that originates in the 401 Robert Building delivers letters through the underground service tunnel. Electronic cars about the size of a computer monitor run on a mile-long aluminum track installed throughout the buildings, carrying mail to preprogrammed stations. The $1 million system enabled Minnesota Life to reduce mailroom personnel and the 400 Robert Building regained nearly a story.
St. Paul's growth strategy involves 10 guiding principles that encourage the development of mid-rise buildings that are pedestrian-friendly and that present a welcoming face to the street. In addition, 401 Robert, which occupies a full block at the city's center, needed to bridge the historic red brick structures of the lower downtown area with the gray stone towers of St. Paul's business center. According to DeAngelo, "St. Paul is not a city of skyscrapers — and 401 Robert is definitely designed with the neighborhood and the city in mind." Therefore, the building's exterior features a mix of same gray granite of the 400 Robert structure, red granite that echoes the lower downtown area, two-story-high windows that provide a sense of mass and an assortment of precast-concrete wall panels that provide weight. "The goal was that the building's exterior reflect the same scale as its neighbors in order to create a comfortable environment for the pedestrian," he said.
A friend to pedestrians
Key to creating a pedestrian-friendly environment are the building's skyways and four-levels of underground parking. St. Paul has an elaborate system of structural steel and glass skyways that connect the downtown area. The site of 401 Robert originally housed a collection of three buildings with four skyways extending to adjacent buildings. Before the site was cleared for construction, Meyer, Borgman and Johnson was charged with developing temporary shoring for the skyways using 45-ft.-deep concrete caissons. After relying on the shoring for two years, the skyways were reattached.
The building's four levels of underground parking demanded even more creativity. Originally, the design involved an above-ground structure that occupied half the block, with the new office tower sited on the remaining land. But this design would challenge the city's guiding principles and limit the size of the floor plates. "Even though the city has an intricate skyway system, it is very interested in keeping its streets alive," says DeAngelo. "Placing the parking underground makes the streetscape and building pedestrian-friendly on all four sides."
The earth below the site had a layer of soft clay that varied in depth from 15 to 26 feet. According to Michael Ramerth, structural engineer with Meyer, Borgman and Johnson, this soft clay presented very high lateral earth pressures that in turn significantly affected the design of the site retention system and the design of the parking area's 18-in.-thick foundation walls. As a result of the decision to place the parking underground, the soft clay within the building's footprint was excavated and the building was founded on a series of spread footings and shallow caissons that bear directly on sandstone bedrock below the clay. From this foundation, 44-in.-thick square building columns support the parking structure's cast-in-place concrete plates as well as the tower's wide-module pan-and-joist concrete system.
The joint effort of the building team has paid off. "We've had an excellent response from employees," says Fesser, who recently conducted a survey of the occupants. "I think the biggest testimony to the building's success is the simple fact that it does what it was designed to do — serve the company and the community."
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Renee Young is a freelance writer based in Mundelein, Ill., and a former editor of BD&C.